NOTCH signaling pathway and Acute Lymphoblastic Leukemia

1. NOTCH signaling pathway and Acute Lymphoblastic Leukemia Cecilia Varnagy-Moskovitz

2. Definitions. • Leukemia: “group of bone marrow diseases involving an uncontrolled increase in WBC.” (Medical Encyclopedia). • Acute: fast development of the disease. • Lymphocytic: is develop from lymphocytes.

3. Definitions • Hematopoiesis: process of development of blood cells. • Second messenger: system where an intracellular signal is generated in response to an intercellular stimulation. • Ligand: molecule that binds to another.

4. Definitions • NOTCH: “gene family that encodes single pass trans-membrane receptors able to transduce intercellular signals involved in cells-fate determination”. (Kojika). • JAGGED1: important ligand for NOTCH signaling pathways. • Signal pathway: transference of information through a channel, mediated by second messengers.

5. Fevers or night sweats. Headache. Bleeding. Swollen lymph nodes. Frequent infections. Feeling weak or tired. Pain in bones or joints. Weight loss. Symptoms of Leukemia.

6. Diagnosis of leukemia. • Physical exam. • Blood test. • Biopsy. • Cytogenetics. • Spinal tap. • Chest X-ray.

7. Treatment for Leukemia. • Chemotherapy. • Biological therapy. • Bone marrow transplantation.

8. A wide role for NOTCH1 signaling in acute leukemia Chiaramonte, Raffaella et al.

9. NOTCH signaling and acute leukemia • Basic terms we need to know: • T-acute lymphoblastic leukemia (T-ALL) • Acute myelogenic leukemia (AML) • B-cell precursor ALL (BCP-ALL) • Delta/Serrate/ Lag2 ligands (DSL)

10. NOTCH signaling and ALL • NOTCH pathway has a role in the process of hematopoiesis. • NOTCH1 is related to the development of thymocites. • NOTCH1 needs to be active in earliest stages of T-cell commitment in thymus to be able to develop T-lymphocytes. • If this doesn’t happen B-lineage will be developed.

11. NOTCH signaling and ALL • NOTCH1 has also important role in signaling alterations in pathogenesis of T-ALL. • T-ALL patients present a translocation that leads to over expression of NOTCH1 • NOTCH pathway is activated in T-ALL cell lines.

12. Materials and Methods • Pediatric patients: • 32 children with T-ALL • 25 with BCP-ALL • 20 with AML Cell lines used were: T-ALL and B-cell derived leukemia/lymphoma.

13. Materials and Methods • Extraction of RNA and retro-transcripted. • PCR test and amplifications. • Amplified DNAs separated by electrophoresis. • Results analyzed by ANOVA (analysis of variance) test

14. Question!! • What is the gene expression involved in NOTCH pathway activity related with three groups of patients: T-ALL, BCP-ALL, and AML???

15. Hypothesis. • Ho= gene expression values are equal across the different cell types. • H1= at least two cell types gene expression values are different. For rejection of H0 P<0.01

16. Comparison test • To know which particular population differs from others. • To have a significant difference P<0.05.

17. Test and results • Analysis of T-ALL cell lines and DSL ligands. (control: lymphoma cell line) • In all T-ALL cell lines expressed at least one ligand. • Comparison of expression values of NOTCH related genes (NOTCH1, HES1, pT , and JAGGED1)

18. Results • After comparison of the three groups: • NOTCH1 levels in T-ALL and AML were equivalent, but higher than BCP-ALL (P<0.01) • For HES1 and pT, T-ALL present highest levels of expression, compared to AML and BCP-ALL. • JAGGED1 is more frequent in AML than T-ALL and BCP-ALL.

19. Conclusions. • Cell fate is regulated by NOTCH1 • NOTCH1 interferes in cell differentiation • NOTCH1 helps avoid apoptosis of T-cell lineage differentiation • T-ALL present high levels of NOTCH1 • High level of pathway activity is related to NOTCH ligands

20. Conclusions • JAGGED1 expression related to differentiation in hematopoietic progenitors. • JAGGED1 has no relation with NOTCH pathway • NOTCH1 has an important role in T-ALL

21. Thank you Questions